M-Cell Half Cell: 1 cm² Multipurpose Electrochemical Cell

M-Cell Half Cell: precision three-electrode research

The M-Cell Half Cell is a 1 cm² research cell developed for classical three-electrode electrochemical experiments. It provides a reproducible and chemically robust alternative to traditional beaker cells, while retaining the modularity and reference electrode precision of the full M-Cell platform.

Advantages over traditional three-electrode setups

Compared to conventional beaker-type three-electrode cells, the M-Cell Half Cell provides:

• Accurate reference electrode placement: Luggin capillary arrangement guides the measurement point to within approximately 0.2 mm of the intended location.
• Fixed, reproducible geometry: the mechanical structure ensures that working, counter, and reference electrodes remain in the same spatial relationship between experiments.
• Controlled electrolyte flow: flow can be created through the working electrode, enabling studies of electrochemical kinetics under defined mass transport. This provides capabilities comparable to a rotating disk electrode (RDE), while remaining applicable to porous electrode materials where RDE setups are limited.
• Full chemical compatibility: all non-active components are made from PEEK, PTFE, EPDM, and VITON.

Typical applications

• Cyclic voltammetry: flowing-electrolyte CV measurements on planar or porous electrodes.
• Catalyst screening: the 1 cm² active area is well-suited for testing precious metal catalysts (e.g. Pt, Ir, Ru) or novel catalyst formulations where sample quantity is limited.
• Half-cell battery testing: evaluate individual electrode performance in redox flow battery development.
• Half-cell electrolyser testing: isolate anode or cathode behaviour in water electrolysis research (AWE, AEM, PEM).
• Half-cell CO₂ reduction: investigate cathode-side CO₂RR performance with a well-defined reference.
• Corrosion studies: flowing-electrolyte corrosion testing with a precisely located reference electrode.
• Kinetic studies: controlled mass transport through porous electrodes for extraction of kinetic parameters.

Operating configurations

The M-Cell Half Cell supports the following configurations from the M-Cell platform:

1. configuration G-1, half-cell operation with wire counter electrode: the M-Cell flow body contains the working electrode, while a wire counter electrode is placed externally in the electrolyte reservoir.
2. configuration G-2, half-cell operation with flow body counter electrode: a second flow body (from another M-Cell Half Cell or from an M-Cell Full Cell) houses the counter electrode. The spacing between working and counter electrode can be adjusted with spacer gaskets.
3. configuration H, flexible Luggin capillary placement: an OD 1/16” tube can be used as a Luggin capillary directed to almost any point in the cell, allowing custom reference electrode placement.

Reference electrode system

The M-Cell Half Cell uses Luggin capillary based reference electrode arrangements, with the reference electrode held in an external flow-through holder. The measurement point is guided through channels in the cell and gaskets to a defined location inside the cell.

The reference electrode circuit can be operated in:

• dead-end mode (using a syringe): eliminates shunt currents, simpler setup, may require occasional refilling if gas bubbles enter the circuit.
• pump mode (continuous electrolyte flow through the reference holder): prevents gas bubble accumulation, small shunt-current correction may be needed (see assembly manual for details).

Scaling up to a full cell

Two M-Cell Half Cell units can be combined to form:

• a flow-body based three-electrode setup (Configuration G-2), or
• a full M-Cell flow cell for closed cell, open cell, or three-compartment operation, with appropriate gaskets and a second current collector.

For research programmes that require both half-cell and full-cell measurements, purchasing an M-Cell Full Cell or two M-Cell Half Cells can be considered.

System integration

The M-Cell Half Cell can be operated in any suitable beaker or reservoir. For controlled-environment experiments, the Multiport Electrolyte Reservoir was co-developed with the M-Cell to enable:

• sealed, oxygen-free, or CO₂-saturated electrolyte environments
• temperature control up to at least 95 °C
• flexible electrolyte sampling and management

Electrical connections

The M-Cell Half Cell uses a 4-wire configuration (I+, U+, I−, U−) with ø0.7 mm wires in titanium, nickel, or 316L stainless steel. Wire quick connectors are included for fast and robust connections to a potentiostat or power supply.

Gaskets and electrode thickness

The M-Cell Half Cell is supplied without gaskets. Gaskets are ordered separately to match the specific application. The gasket type and thickness define the electrode compression and the reference electrode measurement area. See the assembly manual for detailed guidance on gasket selection for each configuration.